Unvented Gas Logs
Unvented gas logs interact with the house for intake and
exhaust. Just as with conventionally vented apliances, unvented gas
logs are required to have prescribed permanent openings to provide all
air from outdoors (both for confined and unconfined spaces). Also in
confined spaces in normal construction, air for unvented gas logs can
be provided all from outdoors, all from adequately sized interior spaces,
or from a prescribed combination of indoor and outdoor sources.
No unvented gas appliance can be installed in a confined
space used as a bathroom or bedroom, regardless of construction tightness.
There are special requirements, however, for unvented appliances in
unconfined bedroom/bathroom spaces, both in normal and unusually tight
construction. Only one wall-mounted unvented appliance, with an input
rating not exceeding 6,000 Btu/hr. in a bathroom or 10,000 Btu/hr. in
a bedroom can be installed. If the unconfined space is in a house of
unusually tight construction, a source supplying air all from the outdoors
(or an engineered make-up air system) must be provided. It is important
to keep the intake screen clean to allow free flow of combustion air.
